The present invention relates to a coke oven battery and, more particularly, to a reversing apparatus with an automatic change over feature which is used when firing of the battery is changed from one type of gas to another type of gas. That is, the reversing apparatus of the present invention automatically controls the reversal of the flow of air and waste gas through the vertical flame flues of the heating walls, and controls the flow of fuel gas and combustion air to the flame flues.
Those skilled in the art recognize that the control of the flow of fuel gas and combustion air to two groups of flame flues, and the control of the flow of waste heat from the same two groups of flame flues, increases the number of sequential steps in the proper operation of a coke oven battery. The steps must be timed to occur in a preselected sequence. All of the control components associated with the respective groups of flame flues must be actuated in a matched sequential manner. It is necessary for maximum safety that the actuators be positively interlocked to ensure proper sequential operation.
Additionally, in a coke oven battery operation, it is necessary or desireable from time to time to change over from burning one kind of fuel to another kind of fuel. Heretofore, coke oven batteries have been built in such a way that the flame flues can burn either rich, or coke oven gas, or lean, or blast furnace gas.
In order to change over from burning one type of gas to another type of gas under maximum safe conditions, a prescribed sequence of steps are performed in opening and closing valves that control the flow of rich gas and lean gas. Certain manual operations to accomplish the desired change over have, heretofore, been performed. The present invention, however, performs the required operations automatically and in proper sequence.
A general list of the operations that were formerly done manually are:
1. The air valve lids on all reversing boxes fitted for lean or blast furnace gas would be latched when firing with such lean gas. The same air valve lids would be unlatched when firing with rich or coke oven gas; PA1 2. When firing with lean or blast furnace gas, all of the lean gas shut-off valves would be opened; PA1 3. When firing with rich or coke oven gas, all of the lean gas shut-off valves would be closed; and PA1 4. When firing with lean or blast furnace gas, the air setting of the air valves on all boxes not fitted for blast furnace gas would be changed by removing or adding finger bars therein; finger bars would be removed, thereby increasing the air opening, when firing with lean or blast furnace gas, and finger bars would be added, thereby decreasing the air opening, when firing with rich or coke oven gas.
In coke oven batteries that are fired with mixed gas through the rich gas system simultaneously with lean or blast furnace gas through the sole flues, additional change over steps are required. It should be noted that, when changing from rich gas to lean gas firing, the change over time for these steps is most critical. When changing from rich to mixed gas underfiring, the flow rate of the rich gas must be substantially reduced, and this reduced flow is mixed with lean gas.
On a battery with end flue heating (separate gas flow to the two end flues on each side of the battery) there are a minimum of three valves that must be opened, closed or repositioned.
On change over from mixed gas to rich gas underfiring, these same three valves must be changed over.
Where a battery is fired by burning only lean or blast furnace gas, or by burning only rich or coke oven gas, the number of valves to change is reduced from three to one.
Those skilled in the art will, from the following description of one embodiment of the present invention, understand that it performs all of the normal reversing functional steps and, in addition, performs all of the aforementioned manual change over steps at any reverse neutral position at the discretion of the battery control operator by selecting a control mode on the control panel in the battery reversing room or at some other designated operating station.